Patient Safety and Quality of Care

Antibiotics are overprescribed, particularly for acute nonspecific respiratory infections (ARIs), which are usually caused by viruses. Thus patients who receive antibiotics for ARIs are potentially exposed to antibiotic side effects with an anticipated small risk of receiving a benefit. Even with practice guidelines recommending against antibiotic treatment for ARIs, one-half of all U.S. and U.K. adults diagnosed with ARIs receive antibiotics.

A new study found that patients treated with antibiotics for ARIs are not at increased risk of severe adverse drug events requiring hospital admission, compared with ARI patients who don't receive antibiotics. In addition, these patients had a slightly decreased risk of being hospitalized for pneumonia.

The study, based in the United Kingdom, used prescription and outcome data to identify 1,531,019 visits by 814,283 adults to primary care providers with an ARI diagnosis. The researchers compared the outcomes of patients prescribed antibiotics with those of patients not prescribed antibiotics. Particular attention was paid to hospitalizations within 15 days for severe adverse drug events and community-acquired pneumonia. In 65 percent of all ARI visits, antibiotics were prescribed. Antibiotic prescribing varied widely among the 326 practices in the study, ranging from 3 percent to 95 percent of visits.

In terms of preferred antibiotics, amoxicillin was at the top of the list (51.2 percent), followed by penicillin (17 percent) and erythromycin (12.7 percent). Those who did receive antibiotics tended to be older and had more coexisting conditions. The researchers identified 126 severe adverse events. Among those receiving antibiotics, the crude incidence rate of events was 8.48 events per 100,000 visits. In the group not receiving antibiotics, the crude incidence rate was 7.75 events.

Adjusting for age, study year, coexisting conditions, and clustering by practice, there were 1.07 fewer severe adverse events per 100,000 visits for treated vs. untreated patients, but this was not statistically significant. None of the individual antibiotic classes showed any increased risk for these events. However, antibiotic treatment was associated with minor adverse events, with 55.58 extra events per 100,000 visits requiring outpatient followup. In the case of pneumonia hospitalizations, there were estimated to be 8.16 fewer hospitalizations per 100,000 visits for patients prescribed antibiotics, which was statistically significant.

According to the researchers, 12,255 patients needed to be treated with antibiotics to prevent just 1 hospitalization for pneumonia. The study was supported in part by AHRQ (HS16946).